Magnetic latch attachment with relays

ABSTRACT

A permanent magnet latch attachment which magnetically latches an electromagnetically driven contact carrier of an electromagnetically operated switch device in an operating position against the force of a biasing spring which, when the latch attachment is rendered inoperative by energization of a release coil, returns the carrier to starting position. A connecting pin is rotatable about an axis eccentric to its own axis adjusts the flux gap of the latch. The latch attachment and release coil are mounted between the rear of the relay base and a mounting panel for the relay.

0 United States Patent [111 3,569,878

[72] Inventors William E. Grass [56] References Cited kvliefsgl B Dee Wis UNITED STATES PATENTS 5 49688 [211 App]. No. 821,614 3,377, 19 /l tong 317/157 [22] Filed May 5, 1969 Primary Examiner-Harold Broome [45] Patented Mar. 9, 1971 Attorney-John H. Leonard [73] Assignee Square D Company Park Ridge, 1]].

ABSTRACT: A ermanent magnet latch attachment which t'lll h lt t'lld' tat magne ica y atc es an e co romagne ica y riven con c [541 LATCH ATTACHMENT WITH carrier of an electromagnetically operated switch device in an 9 4 Bra in 1 operating" position against the force of a biasing spring which,

w gFigs' when the latch attachment is rendered inoperative by ener- [52] US. Cl 335/170, gization of a release coil, returns the carrier to starting posi- 335/132 tion. [51] Int. CL H0lh 9/24 A connecting pin is rotatable about an axis eccentric to its [50] Field of Search 335/132, own axis adjusts the flux gap of the latch.

165,166, 167, 169, 170, 174, 179, 253, 254, 229; 317/157 (Cursory) The latch attachment and release coil are mounted between the rear of the relay base and a mounting panel for the relay.

Patented March 9, 1971 3,569,878

2 Sheets-Sheet l M v NVENTORS ATTORNEY,

MAGNETIC LATCH ATTAQHMENT WITH RELAYS The present latch attachment is described herein for purposes of illustration in combination with a relay such as disclosed in the application of Allin W. Schubring and Kenneth Fe. Paape, Ser. No. 759,382, filed Sept. l2, 1968, now US. hat. No. 3,501,717 and entitled Convertible Contact Structure for an Electromagnetically Operated Switch, and in the application of Kenneth J. Marien, Ser. No. 759,381, filed Sept. 12, 1968, now US. Pat. No. 3,50l ,723 and entitled Coil and Stationary Magnet Mounting for an Electromagnetically Operated Device.

A principal object of the invention is to provide a magnetic latch attachment which is simple and compact in construction, and is arranged in a housing that can readily be installed so as to be between the supporting base of the relay and a panel on which the relay is mounted.

Another object is to provide in the latch attachment a simple and effective rotatable adjusting means which carries an eccentric pin interconnecting the movable contact carrier of the relay and a latch member of the attachment, and so arranged as to be operable to adjust the effective flux gap of the attachment in relation to the position of the contact carrier.

Various other objects and advantages will become apparent from the following description wherein reference is made to the drawing in which:

FlG. l is a front elevation of an electromagnetic relay or switch device combined with the magnetic latch attachment of the present invention;

FIG. 2 is a right side elevation of the structure illustrated in FIG. 1, showing the latch attachment at the rear of the electromagnetic relay, parts of the attachment being shown partially in section for clearness in illustration;

FIG. 3 is a front elevation of the latch device and its housing with the electromagnetic device removed, as viewed from line 3-3 in FIG. 2; and

FIG. 43 is a diagrammatic illustration of the release coil of the electromagnetic device showing it adapted for an alternating voltage circuit.

Since the electromagnetic relay illustrated is discussed in detail in the above entitled copending applications, it is described only briefly herein.

Referring to the drawings, this relay, indicated generally at l, is mounted on the forward face of a die cast metal supporting base 2 which is adapted to be mounted on the forward face of an upright supporting panel P, indicated in dot-dash lines.

The device comprises generally an encapsulated electromagnetic coil 3 having a laminated field piece 4 secured by a single screw 5 in a fixed position on the base 2. The device includes an armature 6 movable upwardly and downwardly, in the installed position of'the relay as illustrated in FIGS. 1 and 2, and having an upright center pole piece 7 received in the central passage of the coil 3.

A movable contact carrier it) is mounted in suitable guideways on the base 2 for movement, parallel to the path of the armature 6, to contact making and breaking positions, respectively. The carrier 10 is connected to the armature 6 by a pin ii and carries a plurality of movable contacts 12. A stationary support 13 is mounted on the base 2 and carries stationary contacts M complementary to the movable contacts on the carrier 10.

The armature 6 is movable upwardly by the coil 3 when the coil 3 is energized and, upon deenerg'ization of the coil 3, is returned downwardly to starting position by a biasing spring 15 which is disposed in a recess in the base 2 and bears against a lug 16 on the rear end of the movable carrier 10. The contacts may be normally open and are closeable by upward movement of the carrier, or may be normally closed and are openable by downward movement of the carrier, depending on the use to which the relay is to be put.

The structure thus far described is known in the art and the improvement herein resides in the magnetic latch attachment for latching the movable contact carrier magnetically in the upward position to which driven by energization of the electromagnetic coil 3.

All of the operating parts of the electromagnetically operated relay are carried by the base 2 at its forward upright face. The parts of the magnetic latch attachment are mounted at the rear face of the base 2 so as to lie between the base 2 and the supporting panel P to which the base 2 is connected for supporting the relay.

For mounting the latch attachment in this manner, a suitable housing 20, preferably of die cast metal, is provided. The housing 20 has a rear wall 21 adapted to be juxtaposed against the front face of the panel P, and has forwardly projecting sidewalls 22 which at their forward edge are juxtaposed against the rear face margins of the supporting base 2. The housing 2f has suitable bores 23 through which bolts 24 are received. The inner ends of the bolts are in threaded engagement with the base 2 so that the rear wall of the base 2 provides a cover closing the front of the'housing 20.

Mounted within'the housing is a permanent magnet assembly 25 which comprises a front pole piece 26, a rear pole piece 27, and permanent magnet means 28 clamped therebetween. The pole piece 27 has a tongue or extension 27a, and is mounted on a carrier 29 which is has a tongue or extension 29a. The extension 27a is mounted in guides 36 formed in the housing 20 and extending parallel to the path of movement of the movable carrier 10. The guides 30 are arranged to overlie the lateral longitudinally extending margins of the extension 27a so as to prevent the permanent magnet assembly from being pulled outwardly forwardly from the housing 20, but with sufficient edgewise clearance to permit the extension 27a to move laterally a short distance. The tongue 29a of the carrier 29 is guided between lateral guideways 31 also formed on the base 2. The extension 27a is provided with a forwardly extending pin 32 which 'forms part of an adjustable connecting means 33 for connecting the carrier 29 of the permanent magnet assembly to the movable contact carrier ll).

The connecting means 33 comprises a body 34 having a pin 35 thereon. The pin 35 is received in, and rotatable in, a suitable bore 36 in one end of a pin ll mounted on the carrier. The forward end of the pin ll is received with operating clearance in a bore 37 in the armature 6 so as to move therewith and with the movable contact carrier 19 as the movable contact carrier 10 is moved to its contact making and contact breaking positions, respectively, by the armature 6. The body 34 has a bore 38 the axis of which is eccentric to the axis of the pin 35. The bore 38 receives the pin 32 which thereby supports the body 34 for rotation about the axis of the pin 32. Thus by rotating the body 34 about the axis of the pin 32, the relative positions of the movable contact carrier 10 and the carrier 29 of the permanent magnet assembly 25 can be adjusted lengthwise of the path of movement of the carriers. A suitable lock screw 39 is provided for locking the body 34 fixedly relative to the pin 32 in the rotated position selected. The edgewise clearance between the tongue 27a and guide 30 compensates for the lateral movement of the pin 35 due to its eccentric relation to the pin 32.

Thus, the permanent magnet assembly 25 is movable by the armature 6 in one direction upon energization of the electromagnetic coil 3 and is moved in the opposite direction by the force of the biasing spring 15 applied by way of the carrier 10.

The magnet assembly 25 holds the movable contact carrier 10 in the position to which the carrier 10 has been driven against the force of the biasing spring 15 by energization of the electromagnetic coil 3, until the operator desires to release the latch thereby to permit return of the carrier 10 by the spring 15.

A magnetic release coil 10 is mounted in the housing 20 and is connected by suitable leads ii to connectors 42 for connecting it in a suitable control circuit,-for instance, in a circuit closed by the Off button of a pushbutton switch. The coil 40 is provided with pole pieces 43 which are arranged at its opposite faces and which have central bosses or core portions 44, respectively, received in the central passage of the coil 40. The pole pieces are secured to the rear wall of the housing 20 in embracing relation to the coil 40 by means of a bolt 45. The pole pieces 43 have intumed flanges 46 with a flux gap 47 between their 144 adjacent edges. The flanges 46 are arranged in spaced relation to the movable permanent magnet assembly 25 when the permanent magnet assembly is in its fully retracted position, which is the position assumed when the movable contact carrier is biased to its starting position by its spring 15. This spaced relation preferably is such that when the permanent magnet assembly is moved by energization of the electromagnetic coil 3 to the upward operating position of the movable contact carrier 10, the permanent magnetic pole pieces 26 and 27 on the one hand and the flanges 46 of the pole piece 43, on the other hand, are in intimate contact with each other. The permanent magnetic attraction is such that, so long as the coils 3 and 40 are unenergized, the carrier will be held latched magnetically in the position to which it had been moved by energization of the coil 3.

The coil 40 is so wound that, when energized, the flux therefrom is in opposition to the attractive flux between the permanent magnet assembly 25 and the pole pieces 43, and is sufficient so that the algebraic sum of the fluxes of the coil and the permanent magnet assembly 25 provides a resultant reduced flux incapable of holding the permanent magnet assembly 25 in latched position against the force of the biasing spring 15. Accordingly, upon energization of the coil 40 while the coil 3 is deenergized, the permanent magnet assembly 25, and its carrier 28 are released, and the spring thereupon returns the movable contact carrier 10, armature 6, and permanent magnet assembly 25 to starting position.

Since the base 2 of the relay can be secured to the housing of the magnetic latch attachment, the entire combination can be securely installed onto the panel P by means of suitable bolts or screws passed through appropriate recesses 50 in the rear wall 21 of the housing 20, and the bolts 24 connecting the base 2 to and housing 20.

When the relay is energized, the armature 6 moves upwardly until its pole faces are in tight engagement with the pole faces of the field piece 4, and the parts of the permanent magnet latch assembly are tightly engaged with each other. When the relay coil 40 is deenergized, the armature 6 drops downwardly slightly to provide an air gap of 0.005 inches between the pole faces of the armature 6 and field piece 4 while the pole pieces 46 remain in firm engagement with the pole pieces 26 and 27 of the magnetic latch attachment. This air gap is the result of a slightly loose or sloppy fit between the parts connecting the armature 6 and the permanent magnet.

As described in the above-entitled applications, the relay is arranged so that is its parts can be readily removed for servicing and replacement. The present magnetic latch attachment is such as not to interfere with the removal and reassembly of the parts of the relay. Further, upon removal of the relay from the front of the housing 20, the pole pieces 43, coil 40, and permanent magnet assembly can readily be removed from the housing 20 and serviced and reassembled. I

In may in many instances, it is'desirable the magnetic latch attachment be arranged for operation in circuits employing a source of alternating current. We When to be used for such purposes, the encapsulated release coil 40 may have suitable capacitors and diodes incorporated in the circuit therewith. For example, as shown in FIG. 4, the coil 40 has at each of its terminals a capacitor 51 and diode 52 which are connected in parallel with each other and the resultant parallel circuit is connected in series with the coil 40.

Various other arrangements for this purpose, depending upon the type of range of voltage with which the latch attachment is to be used may be provided.

We claim:

1. An electromagnetically operated switch device including:

a base;

a movable contact carrier mounted on the base for movement in opposite directions along a predetermined path to contact making and contact breaking positions, respectively;

a permanent magnet assembly;

a magnetically attractive assembly;

a support supporting one of the assemblies for movement along a predetermined path;

connecting means connecting a movable one of said assemblies to the carrier for movement in a fixed relation to the movement of the carrier;

biasing means biasing the carrier to one of said positions;

an electromagnetic means carried by the base and operative when energized to drive the carrier against the force of the biasing means to the other of said positions; said assemblies having poles normally spaced apart when the carrier is held by the biasing means in said one position; and the movable one of said assemblies being movable sufficiently close to the other of said assemblies so that the assemblies will be held magnetically in fixed relation to each other after the carrier has been moved to said other position against the biasing force of the biasing means and the electromagnetic means has been deenergized; and I an electromagnetic release coil arranged when energized, to produce magnetic flux in opposition to the magnetic flux of the permanent magnet assembly sufficient to render the resultant flux attraction between said assemblies inadequate to hold the carrier in said other position against the force of the biasing means.

2. The structure according to claim 1 wherein:

said base has a wall;

said carrier, electromagnetic means, and biasing means are mounted on the base in front of said wall; and

said assemblies and release coil are disposed at the rear of said wall.

3. The structure according to claim 2 wherein the support is an open front housing juxtaposed at its front against the rear of said wall and enclosing said assemblies and release coil between the wall of the base and a mounting panel when the switch device is installed in operating position on an instrument panel.

4. The structure according to claim 3 wherein the base and said housing each is an open front die casting.

5. The structure according to claim 2 wherein:

lineal guideways are provided on the front of said wall of said base;

the carrier is mounted in the guideways for reciprocation along its said path;

the connecting means comprise additional lineal guideways in the housing parallel to the guideways on said wall of the base and a second carrier mounted in said additional guideways and supporting the movable one of said assemblies for movement with the second carrier; and

said movable assembly includes a permanent magnet.

6. The structure according to claim 5 wherein the second carrier is a pole piece of the permanent magnet assembly.

7. The structure according to claim 5 wherein the magnetically attractive assembly comprises two plates of flux conducting material in face to face spaced relation to each other and secured in the housing each with an end face facing toward the permanent magnet assembly and providing poles for the release coil;

said plates have centering bosses of flux conducting material extending from their adjacent faces, respectively, and received in, and positioning, said release coil in the housing and providing a core therefor.

8. The structure according to claim 1 wherein said connecting means comprises a first part connected to said movable assembly for rotation about a predetermined axis extending transversely of said path, and a second part in fixed position relative to the first part, and connected to the movable contact carrier for rotation relative thereto about another axis parallel to and offset radially from said predetermined axis; and

means for securing one of said parts against rotation in selected rotated positions thereof, respectively.

9. The structure according to claim 1 wherein the permanent magnet assembly is positioned at all times relative to the electromag rie tF E555?) marine flux path of the permanent magnet assembly is separate and distinct from, and isolated magnetically from, the flux path of the electromagnetic means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,5 9, 7 Date March 9 1971 Inventor) William E. Grass and Robert D. Boley It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Page 1, Col. 2, add the following references: 3,123,306 11/1963 Abendroth 335/179 33 5 9 Conner 335/17 Abstract, Line 8, "is" should be removed. Col. 2, Line 21, "is" should be removed.

2, Line 68, "1-6" should read -I-O-- Col. 3, Line ,3, 7144" should be removed.

3, Line 49, "is" should be removed.

3, Line 56, .In may" should be removed.

3, Line 58, .We" should be removed.

Signed and sealed this 7th day of September 1971 (SEAL) Attest:

EDWARD M.FLETCHER, JR. ROBERT GOTTSCHALK Attesting Officer Acting Commissioner of Pate 

1. An electromagnetically operated switch device including: a base; a movable contact carrier mounted on the base for movement in opposite directions along a predetermined path to contact making and contact breaking positions, respectively; a permanent magnet assembly; a magnetically attractive assembly; a support supporting one of the assemblies for movement along a predetermined path; connecting means connecting a movable one of said assemblies to the carrier for movement in a fixed relation to the movement of the carrier; biasing means biasing the carrier to one of said positions; an electromagnetic means carried by the base and operative when energized to drive the carrier against the force of the biasing means to the other of said positions; said assemblies having poles normally spaced apart when the carrier is held by the biasing means in said one position; and the movable one of said assemblies being movable sufficiently close to the other of said assemblies so that the assemblies will be held magnetically in fixed relation to each other after the carrier has been moved to said other position against the biasing force of the biasing means and the electromagnetic means has been deenergized; and an electromagnetic release coil arranged when energized, to produce magnetic flux in opposition to the magnetic flux of the permanent magnet assembly sufficient to render the resultant flux attraction between said assemblies inadequate to hold the carrier in said other position against the force of the biasing means.
 2. The structure according to claim 1 wherein: said base has a wall; said carrier, electromagnetic means, and biasing means are mounted on the base in front of said wall; and said assemblies and release coil are disposed at the rear of said wall.
 3. The structure according to claim 2 wherein the support is an open front housing juxtaposed at its front against the rear of said wall and enclosing said assemblies and release coil between the wall of the base and a mounting panel when the switch device is installed in operating position on an instrument panel.
 4. The structure according to claim 3 wherein the base and said housing each is an open front die casting.
 5. The structure according to claim 2 wherein: lineal guideways are provided on the front of said wall of said base; the carrier is mounted in the guideways for reciprocation along its said path; the connecting means comprise additional lineal guideways in tHe housing parallel to the guideways on said wall of the base and a second carrier mounted in said additional guideways and supporting the movable one of said assemblies for movement with the second carrier; and said movable assembly includes a permanent magnet.
 6. The structure according to claim 5 wherein the second carrier is a pole piece of the permanent magnet assembly.
 7. The structure according to claim 5 wherein the magnetically attractive assembly comprises two plates of flux conducting material in face to face spaced relation to each other and secured in the housing each with an end face facing toward the permanent magnet assembly and providing poles for the release coil; said plates have centering bosses of flux conducting material extending from their adjacent faces, respectively, and received in, and positioning, said release coil in the housing and providing a core therefor.
 8. The structure according to claim 1 wherein said connecting means comprises a first part connected to said movable assembly for rotation about a predetermined axis extending transversely of said path, and a second part in fixed position relative to the first part, and connected to the movable contact carrier for rotation relative thereto about another axis parallel to and offset radially from said predetermined axis; and means for securing one of said parts against rotation in selected rotated positions thereof, respectively.
 9. The structure according to claim 1 wherein the permanent magnet assembly is positioned at all times relative to the electromagnetic means so that the flux path of the permanent magnet assembly is separate and distinct from, and isolated magnetically from, the flux path of the electromagnetic means. 